How many cows is "a lot"?October 01, 2013

English economist William Stanley Jevons (1835-82) has gone down in history with a research that helped discover a human being´s ability to remember up to seven objects of the same kind at once with the variation of plus-minus two units.

English economist William
Stanley Jevons (1835-82) has gone down in history with a research
that helped discover a human being´s ability to remember up to seven
objects of the same kind at once with the variation of plus-minus two
units.

How he got to discover
this knowledge is even more interesting. Namely, Mr. Jevons picked a
random number of beans, threw them in a box and showed them to the
subjects for only a moment (not long enough to count). After that
the subjects had to guess how many beans were in the box.. The
results showed that with 3-4 beans there were no mistakes and there
were only sometimes mistakes when the box had five beans in it. When
there were ten beans in the box then the subjects were mistaken in
half of the cases and mostly, the results were wrong when the
subjects needed to guess the number of 15 beans. From 1027 tests it
was concluded that "7 plus – minus 2 units" is how many
objects of the same kind is a human being able to remember at the
same time. The results of the research were published in Nature
magazine on the 9th of February in 1871.

This
research, which was conducted 130 years ago, is one of the best
conducted researches in the history of science. Why bring it up? Each
time a barn door is opened and a 60- or 380- or 840-headed cattle
heaves in sight, to the consultant they appear as the random amount
of beans in Mr. Jevons´ test. In order to come to conclusions and
figure out recommendations through the analysis of production
factors, there must be the following chain of questions and answers:
What is the relative status of milk production? Was the quantity of
milk bigger or smaller last year and the year before that? How
different or similar are the results of test milking and milk tank
test? When are the samples taken? Which animals have too low
production? What kind of production results did the beginning of serviceperiod show? How long has a cow
been milked? What kind of effects do diseases or deviations have?
What kind of effects do mastitis (clinical, sub-clinical), lameness
and metabolic disorders have? What is the impact of prolonged calving
interval?

As you see, even before
feed and feeding is included, there are about ten factors that "raise
the number of beans in the box " to the level of 60X10 or 380X10
or 840X10 according to which barn door is opened.

The example above
describes how fast the plurality of causes and complexity of analysis
is growing. It also characterizes how quickly a person´s ability to
analyze the situation runs out. It is true though that there is a
parameter which is difficult to define – intuition. It is a
cognitive skill to sense what is going on in the barn. Unfortunately,
sometimes there is not enough of it.

The more we want to know,
the more data there is. The more data there is, the more difficult it
is to navigate in it. To overcome to problem, there is only one
solution – proper data collection and management. There is no need
to pay for IT solutions until you drop – it is enough to conduct an
analysis with the consultant about the need for information at
beginning of the cooperation. The consultant will then collect the
data necessary and analyze it.